After working throughout the day securing the US-Mexico border members of the U.S. Military stand in line for a drill near the Otay Mesa Port of Entry, California on November 15, 2018.

The Trump administration is spending at least $72 million to send troops to the U.S.-Mexico border as a caravan of migrants arrives to seek asylum. That's nearly double what the White House requested for the entire 2019 fiscal year to hire additional immigration judges to hear the massive backlog of court cases.

Earlier this month, several thousand Central American migrants arrived in Tijuana, Mexico, which borders San Diego. The migrants, fleeing poverty and gang violence, will likely spend months in limbo there as they await their asylum hearings due to the bottleneck in the courts.

Chaos broke out on Sunday as Customs and Border Protection personnel used tear gas to repel some migrants trying to enter the U.S. The Trump administration wants migrants to remain in Mexico while awaiting an asylum decision, which could take months or even years.

The Pentagon estimated that the $72 million will cover the 5,900 troops amassed at the border until Dec. 15. If the mission continues after that date, the costs will increase. The troops are in addition to Border patrol forces, but Trump recently authorized them to use force to protect the agents if necessary.

By contrast, the federal budget allocated just $39.8 million to the Executive Office for Immigration Review for the full fiscal year, which started in October, to hire new judges and support staff, a decrease of 47 percent from the previous year and just 55 percent of what the government is spending to deploy troops to the border for roughly a month and a half.

In the past, Trump's Department of Justice has temporarily deployed immigration judges from other parts of the country to the border. It has not announced such a policy in response to the migrant caravan.

Several lawmakers have criticized the administration's spending decisions.

Alexandria Ocasio-Cortez, a New York City Democrat who was recently elected to the House of Representatives, called out the "financial recklessness" of the administration on Monday.

"What if instead of sending 5k troops to the border, we had sent 5k caseworkers to review + process visa applications?" she tweeted. "In addition to averting moral crisis, it also would've saved enormous amt of resources."

Rep. Joaquin Castro, D-Texas, said in a tweet earlier this month that the president should send more officials to process asylum claims "instead of wasting taxpayer dollars by sending military troops to border."

There are currently 411 judges on staff to adjudicate a backlog of nearly 800,000 pending immigration cases, according to the Executive Office for Immigration Review.

In addition to troops, President Trump is also pushing Congress to approve $5 billion in in funding for a border wall by Dec. 7, threatening a government shutdown.